Abstract: Liquid crystalline ethane derivatives by the described method in order to form liquid crystalline compositions with known liquid crystalline compounds have a general formula I: ##STR1## wherein, if ring A idicates a 1,4-substituted benzene ring, then ring B indicates 1.4-substituted benzene ring or 1.4-trans-substituted cyclohexane ring or 1.4-substituted bicyclo[2,2,2]octane ring or 2.5-substituted pyrimidine ring or 2.5-substituted 1.3- dioxane ring, or if ring B indicates a 1.4-substituted benzene ring, then A indicates 1.4-trans-substituted cyclohexane ring or 1.4-substituted bicylo[2,2,2]octane ring or 2.5-substituted pyrimidine ring or 2.5-substituted 1.3-dioxane ring, and R indicates a normal alkyl chain C.sub.n H.sub.2n+1 or a non-branched alkoxy group C.sub.n H.sub.2n+1 O or an alkylcarboxylic group C.sub.n H.sub.2n+1 COO or an alkyl carbonato group C.sub.n H.sub.2n+1 OCOO or a branched alkyl chain CH.sub.3 --CH.sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.k -- or a branched alkoxy group CH.sub.3 --CH.sub.